Prediction of the amino acid composition of small peptides contained in a plant protein hydrolysate by LC-MS and CE-MS

An original procedure is described to propose the amino acid composition of small peptides (molar mass < 1000 g/mol) contained in a complex vegetable protein hydrolysate. This method is based on two predictive models: the first is related to the peptide hydrophobic character using reversed-phase liquid chromatography-mass spectrometry analysis; the second to the peptide charge-to-mass ratio using capillary electrophoresis-mass spectrometry analysis. A software has been developed to determine the possible amino acid combinations as a function of the mass determination and of the data provided by both models. This computer-aided method has been applied to a rapeseed protein hydrolysate. In the hydrolysate, the amino acid sequence of some unknown vegetable peptides has been determined, using the sequences of native proteins. (c) 2004 Elsevier Ltd. All rights reserved.